In developed countries, it is recognized that water should be treated to kill various microorganisms before being used municipally. It is also recognized that water should be treated effectively before it can be used in swimming pools, hot tubs and spas. Bodies of water such as swimming pools, hot tubs and spas are highly susceptible to rapid micro-organism growth. These bodies of water can rapidly become extremely hazardous to users, unless the water is effectively and continuously treated against micro-organisms.
One common method of treating water against microorganisms is to add chlorine to render the water safe for human consumption and/or use in swimming pools, spas, etc. Normally, chlorine is added to the water in the form of hypochlorite salt or chlorine gas. However, it has been found that chlorine has both an objectionable odor and can cause skin irritations and serious eye irritations to users.
Because of the objectionable physical properties of chlorine, a number of alternate water treatment systems which operate without chlorine have been developed in recent years. One type of alternative water treatment system is a system in which silver ions are added to water to kill the bacteria (see, for example, U.S. Pat. Nos. 4,608,247 and 5,352,369). However, it has been found that, in many cases, systems of this type are only partially effective, and amounts of chlorine must be added to water for complete disinfection.
In one embodiment, the invention pertains to a catalyst for purifying water. The catalyst comprises a substrate, a first metal, and at least one additional metal. The first metal and the additional metals are codeposited onto the substrate. In one further embodiment, the substrate is alumina, the first metal is silver, and the additional metals are selected from the group consisting of platinum, palladium, vanadium, molybdenum, or another transition metal or rare earth metal. Advantageously, the catalyst is capable of disinfecting water such that it meets or exceeds water safety standards.
The invention also pertains to a catalyst for purifying water, comprising a substrate, silver, and palladium. The palladium and silver are codeposited onto the substrate and form a unified structure on the surface of the substrate.
The invention also pertains to a method for purifying water, by contacting water with the catalyst of the invention, such that the water is purified. In one embodiment, purifying the water comprises disinfecting the water.
The invention also includes a method for inactivating microorganisms in water. The method includes contacting the water with a catalyst of the invention, such that the bacteria are inactivated.
The invention also pertains to a device for purifying water comprising the catalyst of the invention. In a further embodiment, the device includes a water inlet, water outlet and a housing which contains the catalyst.
The invention also includes a packaged catalyst for the disinfection of water. The packaged catalyst includes the catalyst of the invention, a container and instructions for using the catalyst for purifying water.